BENDING FAILURE MECHANICS AND BENDING STRENGTH PREDICTION MODELS OF FIBERBOARD BASED ON VERTICAL DENSITY PROFILE

摘要

In order to develop the bending failure mechanics and establish the bending strength prediction models, fiberboards with uniform, "U" shape and "V" shape vertical density profiles (VDP) were manufactured, and their properties were evaluated and compared based on the elastic mechanics and laminated beam theory. The VDP of inertia (T_z) and the decision coefficient of bending failure types (K) were defined and used for building modulus of elasticity (MOE) and static bending intensity (MOE) prediction models. The results showed that the quantifying factors of fiberboard can be divided into panel thickness, maximum density, minimum density and T_z. The fracture failure occurred when K was bigger than 1, while shear failure occurred when Kwas smaller than 1. K was in connection with maximum density, minimum density, panel thickness and T_z. MOE of fiberboard was relevant to T_z and panel thickness. MOR of fiberboard had relation with maximum density, T_z and minimum density. The bending failure mechanics established by this study can explain and predict bending failure effectively and the bending strength prediction